In recent years, there is an increasing demand for further increased speed and increased integration density in integrated circuits of semiconductor devices. This has led to a demand for the development of a multilayer wiring process technique for more efficiently realizing enhanced fineness and multilayering of internal wiring in semiconductor devices. An example of this technique is the formation of groove wiring by embedding of a wiring material such as copper (Cu) in the inside of the groove, for example, by a sputter reflow method or a CVD method and further removing a wiring material deposited the outside of the groove, for example, by CMP (chemical mechanical polishing). By virtue of the advance of the groove wiring technique, in semiconductor devices, the fineness of internal wiring can be increased, and, further, in cooperation with surface flattening by CMP, a higher level of multilayering can be realized.
The enhanced integration density of the integrated circuit has led to a demand for further lowered dielectric of an intermetal dielectric present between wirings, a demand for mechanical strength high enough to withstand the step of removing the wiring material by CMP, and further a demand for chemical resistance to various chemicals, for example, chemicals used in CMP, chemicals used in the removal of photoresist by wet stripping when this method is used, and chemicals for removal of residues after ashing when the removal of the photoresist by ashing is carried out.
Thus, an improvement in quality, for example, further lowered dielectric, enhanced mechanical strength, or improved chemical resistance, is required of electronic materials used in semiconductors, such as intermetal dielectrics (IMDs) and premetal dielectrics (PMDs). To meet these demands, various studies have been made on insulating materials.
Among them, the use of various siliceous materials has also been studied. The siliceous material, however, is generally hygroscopic and thus poses a problem that, in some ambient environment, the specific dielectric disadvantageously increases with the elapse of time.
The use of an organic siliceous film formed by firing of a polyorganosilazane is considered effective for preventing the increase in specific dielectric with the elapse of time. The organosiliceous film thus obtained has such a structure that an organic group is attached to a silicon atom in the silica. Therefore, a siliceous film can be produced which has high water repellency, can suppress a moisture absorption-derived increase in specific dielectric with the elapse of time and, at the same time, possesses heat resistance and environmental resistance required as an insulating film for semiconductors.
Patent document 1: Japanese Patent Laid-Open No. 75982/2002